Lightweight optical elements are important for optical systems that need to be lightweight, such as the imaging systems used in unmanned aerial vehicles (UAVs) and space-based optical systems such as used in spaced-based systems like satellites and unmanned exploration vehicles.
With respect to UAVs, lightweight optical elements are advantageous because they facilitate maximizing flight times for the limited amount of power available, promote better maneuverability, allow for larger apertures and facilitate longer-range viewing (i.e., narrow field of views (FOVs)). Lightweight optical elements also enable movable mirrors having larger apertures and faster movements because the drive motors can be lighter and/or stronger.
With respect to space-based systems, lightweight optical elements are advantageous because of the high cost per weight to launch items into space. Lightweight optical elements also have low inertia, which is important if the space-based system is moving, since less energy is required to get the system moving, keep it moving and bring it to a stop.
Prior art lightweight optical elements rely on either mechanical design or lightweight materials. Mechanical design of lightweight optical elements involves putting ribs in glass, metal or ceramic (ZERODUR, a trademark of Schott AG, Mainz, Germany), or the application of gratings for diffractive optics. Lightweight materials used in the past include low-density materials such as graphite composite materials, foamed aluminum, foamed silicon carbide, and beryllium. ZERODUR has excellent thermal properties, but even when it is ribbed to make the optical element lighter, it is still a relatively dense material (2.53 g/cm3), so that the resulting optical element is still relatively heavy.
Thus, there is a need for even lighter weight optical elements than those currently available.